1. Field of the Invention
The present invention relates to a geared motor used in a driving device for an electric wheelchair.
2. Description of the Related Art
In recent years, a wheelchair is widely used by elderly people who find it difficult to walk, people who move around in a hospital, and people with a mobility impairment, when navigating flat roads, sidewalks, and flat floor in doors.
In many cases, people who use the wheelchair are difficult to manually maneuver its wheels. It is not always possible that there is an attendant with them. Against this backdrop, the so-called electric wheelchair, in which wheel shafts are driven by the power of motors, has been recently proposed in large numbers (refer to, for example, Japanese Patent Laid-Open Publication No. 2000-70304).
FIG. 4 shows an electric wheelchair disclosed in Japanese Patent Laid-Open Publication No. 2000-70304.
A wheelchair 1 comprises a frame 2, safety wheels 4 attached in front of the frame 2 (left side in FIG. 4), driving wheels 5 attached in the rear of the frame 2 (right side in FIG. 4), and an operation control panel 6 attached above and anterior to the frame 2. In this wheelchair 1, a battery 7 and a motor (not illustrated) drive a wheel shaft 12 of the driving wheel 5. The motor is disposed in such a manner that its motor shaft (not illustrated) is in parallel with the wheel shaft 12, and the power of the motor is transmitted to the wheel shaft 12 via a not-illustrated mechanism with parallel gears.
Especially in consideration of use in a hospital and a home, a driving device for the electric wheelchair is required to have low noise. Also, vibration must be as small as possible, in addition to light weight and compact size.
A conventional driving device for the electric wheelchair, however, does not always agree with such requirements.